Impacts of Land Use Changes on Watershed Hydrology: Advancements in Remote Sensing Techniques for Monitoring Hydrological Extremes

Nele Steven^*
*Correspondence: Nele Steven, Department of Energy and Power Engineering, Princeton University, Princeton, NJ 08544, USA, Email:

Keywords

Remote sensing techniques • Hydrology • Agricultural expansion

Introduction

Land use changes, such as urbanization, deforestation and agricultural expansion, significantly alter watershed hydrology. These changes can lead to increased runoff, altered sediment transport and changes in water quality. Monitoring and understanding these impacts are critical for effective watershed management and flood risk assessment. Recent advancements in remote sensing techniques have enhanced our ability to monitor and analyze hydrological extremes, such as floods and droughts, offering new tools for researchers and policymakers. Land use changes, driven by urbanization, deforestation and agricultural expansion, significantly impact watershed hydrology. These alterations affect runoff patterns, sediment transport and water quality, leading to increased risks of flooding, erosion and water scarcity. Understanding and managing these impacts is essential for effective water resource management and mitigating environmental risks.

Recent advancements in remote sensing technologies have greatly enhanced our ability to monitor these hydrological changes. Innovations in satellite imagery, radar remote sensing and LiDAR have provided new insights into land use dynamics and their effects on watershed processes. These techniques enable more accurate and comprehensive monitoring of hydrological extremes, such as floods and droughts, improving our capacity to predict and manage these events. This study explores the effects of land use changes on watershed hydrology and reviews recent advancements in remote sensing techniques. By comparing case studies from different regions, we highlight how these advancements contribute to a better understanding of hydrological processes and support more effective water resource management strategies.

Literature Review

Urbanization increases impervious surfaces, leading to higher runoff and reduced infiltration. This results in more frequent and severe flooding events. Urban areas also contribute to changes in streamflow patterns and water quality degradation due to pollutants and altered hydrological pathways. Deforestation reduces evapotranspiration and increases runoff, which can lead to higher flood risks and reduced groundwater recharge. The loss of forest cover also affects soil stability and sediment transport, impacting downstream water bodies and aquatic ecosystems. Deforestation, the largescale removal of forest cover, has significant and often detrimental effects on watershed hydrology. Forests play a crucial role in maintaining hydrological balance and their loss disrupts various hydrological processes [1]. Forests naturally regulate the water cycle through processes such as interception, transpiration and soil infiltration. Tree canopies intercept rainfall, reducing the amount of water reaching the ground. Additionally, the root systems of trees enhance soil structure, increasing its capacity to absorb water.

When forests are cleared, this natural regulation is lost, leading to increased surface runoff and reduced water infiltration. This can exacerbate flood risks and lead to rapid runoff, which often results in higher peak flows and more intense flooding events. Deforestation exposes soil to the elements, increasing its susceptibility to erosion. Without the protective cover of vegetation, rainfall can directly impact the soil surface, leading to higher rates of soil erosion. Eroded soil particles are carried by runoff into rivers and lakes, causing sedimentation. This sedimentation can degrade water quality, harm aquatic habitats and decrease the storage capacity of reservoirs. Soil erosion also results in the loss of fertile topsoil, which can negatively affect land productivity and increase the need for additional land clearance for agriculture. Forests play a key role in the local and regional water cycle by contributing to evapotranspiration. Trees release water vapor into the atmosphere through transpiration, which helps regulate local humidity and precipitation patterns.

Deforestation reduces evapotranspiration, potentially altering local climate conditions and leading to reduced rainfall and changes in the timing and distribution of precipitation. This disruption can impact water availability and lead to drier conditions in previously forested areas. Deforestation can affect water quality by increasing sediment loads and nutrient runoff into water bodies. The loss of vegetation and the subsequent erosion can introduce large amounts of sediment into rivers and streams, leading to turbid waters and affecting aquatic life. Furthermore, deforested areas are often replaced with agricultural or urban land uses, which can increase the input of pollutants such as fertilizers and pesticides into water systems [2]. Advancements in remote sensing technologies provide valuable tools for monitoring the impacts of deforestation on watershed hydrology. Satellite imagery, including data from Landsat and Sentinel missions, allows for the assessment of changes in forest cover and the subsequent effects on hydrological processes.

Discussion

LiDAR technology offers high-resolution topographic data, which helps in understanding changes in land surface and soil erosion. Additionally, radar remote sensing can monitor changes in surface moisture and vegetation cover, providing insights into the hydrological impacts of deforestation. Agricultural practices, including land tilling and irrigation, can alter runoff patterns and increase sedimentation in rivers and lakes. The use of fertilizers and pesticides can lead to nutrient loading and water quality issues, such as eutrophication. Agricultural expansion, driven by increasing global food demand and economic pressures, has profound effects on watershed hydrology. The conversion of natural landscapes to agricultural land alters the water cycle and has significant implications for water resources and quality. Agricultural practices, including land clearing, tillage and irrigation, significantly impact runoff and infiltration rates. The removal of natural vegetation, such as forests and grasslands, reduces the land's capacity to absorb rainfall, leading to increased surface runoff. This can exacerbate erosion and contribute to higher sediment loads in rivers and lakes. Additionally, intensive irrigation practices can alter the natural flow regimes and increase the volume of water leaving the agricultural area [3].

Agricultural activities, particularly tillage and plowing, disrupt soil structure and increase vulnerability to erosion. Eroded soil particles are transported by runoff into water bodies, leading to sedimentation. Excessive sedimentation can degrade water quality, harm aquatic habitats and reduce the capacity of reservoirs and water storage systems. Soil erosion also depletes nutrientrich topsoil, which can affect agricultural productivity and require additional inputs, further impacting the environment. The use of fertilizers and pesticides in agriculture can lead to nutrient runoff into water bodies. Nitrogen and phosphorus from fertilizers can cause nutrient loading, leading to problems such as eutrophication, which results in algal blooms and decreased oxygen levels in water bodies. Pesticides, on the other hand, can introduce toxic substances into aquatic ecosystems, harming aquatic life and potentially contaminating drinking water sources.

Agricultural expansion can affect groundwater recharge rates. While irrigation can contribute to groundwater recharge in some cases, excessive or poorly managed irrigation can lead to waterlogging and reduced recharge efficiency. Additionally, changes in land use and increased runoff can alter the natural recharge processes of aquifers, potentially leading to reduced groundwater availability in the long term [4]. Recent advancements in remote sensing technologies have improved our ability to monitor and assess the impacts of agricultural expansion on watershed hydrology. Satellite imagery can track changes in land cover and use, while radar and LiDAR technologies provide insights into surface moisture and topography. These tools help in understanding how agricultural practices affect runoff, erosion and water quality, enabling more effective management and mitigation strategies.

Recent improvements in satellite imagery, such as higher resolution and more frequent revisit times, have enhanced our ability to monitor land use changes and their impacts on hydrology. Techniques such as Landsat and Sentinel missions provide valuable data for analyzing land cover changes and their effects on watershed processes. Radar remote sensing, including Synthetic Aperture Radar (SAR), provides valuable information on surface moisture and precipitation. SAR can penetrate cloud cover and provide continuous monitoring of hydrological conditions, which is crucial for flood monitoring and drought assessment [5]. LiDAR technology offers highresolution topographic data, which improves our understanding of watershed characteristics, such as slope and elevation. This data is essential for modeling runoff and sediment transport and for assessing the impacts of land use changes on watershed hydrology.

Conclusion

The comparative analysis of case studies demonstrates the effectiveness of remote sensing techniques in monitoring and analyzing the impacts of land use changes on watershed hydrology. These advancements offer valuable tools for researchers and policymakers to better understand and manage water resources, especially in the face of hydrological extremes. Remote sensing techniques, such as thermal infrared imaging and microwave remote sensing, are increasingly used to monitor hydrological extremes. These methods provide critical information on water surface temperatures, soil moisture and precipitation patterns, helping to predict and manage floods and droughts. This case study examines the effects of urbanization on watershed hydrology in the United States. Remote sensing data from Landsat and SAR were used to analyze changes in land use and their impacts on runoff and flooding.

The study highlights the effectiveness of remote sensing in detecting and monitoring urbanization effects on water resources. In the Amazon Basin, deforestation has led to significant changes in hydrological patterns. Remote sensing techniques, including LiDAR and satellite imagery, were used to assess the impacts of deforestation on water flow and quality. The study demonstrates the importance of remote sensing in understanding and mitigating the effects of large-scale land use changes [6]. Agricultural expansion in Sub-Saharan Africa has led to increased runoff and sedimentation. Remote sensing tools, such as thermal infrared imaging and radar remote sensing, were used to monitor changes in land use and their impacts on water resources. The study provides insights into how remote sensing can aid in managing agricultural impacts on hydrology.

Land use changes have significant impacts on watershed hydrology, influencing runoff, sediment transport and water quality. Recent advancements in remote sensing techniques have greatly enhanced our ability to monitor these impacts and manage hydrological extremes. The integration of remote sensing data with traditional hydrological models provides a more comprehensive understanding of watershed dynamics and supports more effective water resource management.

Acknowledgement

None.

Conflict of Interest

None.

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